An example connectionless-mode transaction server

The following code represents the connectionless-mode transaction server program described in ``Connectionless-mode service''. This server waits for incoming datagram queries, and then processes each query and sends a response.

   #include <stdio.h>
   #include <fcntl.h>
   #include <xti.h>
   

   #define SRV_ADDR	2		/* server's well known address */
   

   main()
   {
   	int fd;
   	int flags;
   	struct t_bind *bind;
   	struct t_unitdata *ud;
   	struct t_uderr *uderr;
   

   	if ((fd = t_open("/dev/tidg", O_RDWR, NULL)) < 0) {
   		t_error("unable to open /dev/provider");
   		exit(1);
   	}
   

   	if ((bind = (struct t_bind *)t_alloc(fd,
   	  T_BIND, T_ADDR)) == NULL) {
   		t_error("t_alloc of t_bind structure failed");
   		exit(2);
   	}
   	bind->addr.len = sizeof(int);
   	*(int *)bind->addr.buf = SRV_ADDR;
   	bind->qlen = 0;
   

   	if (t_bind(fd, bind, NULL) < 0) {
   		t_error("t_bind failed");
   		exit(3);
   	}
   

   	if ((ud = (struct t_unitdata *)t_alloc(fd,
   	  T_UNITDATA, T_ALL)) == NULL) {
   		t_error("t_alloc of t_unitdata structure failed");
   		exit(5);
   	}
   	if ((uderr = (struct t_uderr *)t_alloc(fd,
   	  T_UDERROR, T_ALL)) == NULL) {
   		t_error("t_alloc of t_uderr structure failed");
   		exit(6);
   	}
   

   	while (1) {
   		if (t_rcvudata(fd, ud, &flags) < 0) {
   			if (t_errno == TLOOK) {
   				/*
   				 * Error on previously sent datagram
   				 */
   				if (t_rcvuderr(fd, uderr) < 0) {
   					t_error("t_rcvuderr failed");
   					exit(7);
   				}
   				fprintf(stderr, "bad datagram,
   				  error = %d\n", uderr->error);
   				continue;
   			}
   			t_error("t_rcvudata failed");
   			exit(8);
   		}
   

   		/*
   		 * query() processes the request and places the
   		 * response in ud->udata.buf, setting ud->udata.len
   		 */
   		query(ud);
   

   		if (t_sndudata(fd, ud, 0) < 0) {
   			t_error("t_sndudata failed");
   			exit(9);
   		}
   	}
   }
   

   query(ud)
   struct t_unitdata *ud;
   {
   	/* Merely a stub for simplicity */
   }